1. Field of the Invention
The present invention relates to a power control device for an electronic device, and more particularly, to a power control device for enhancing power stability when the electronic device is powered on and powered off.
2. Description of the Prior Art
An inrush current is a maximum, instantaneous input current drawn by an electronic device when first turned on and is far beyond the electrical specification of the electronic device, therefore, the inrush current easily results in the damage in the electronic device. For the electronic device using an external adapter as a power supply, such as a computer or a printer, there is usually a built-in inrush current restraint circuit in the electronic device for preventing damage. However, the prior art inrush current restraint circuit is implemented by a dedicated protection IC and many passive components, hence high production cost and area cost are required.
In addition, a regulated capacitor with large capacitance is located at the power supply terminal of the electronic device for power stability. When the electronic device is powered off, there is a residual voltage left on the regulated capacitor so that the voltage level of the power supply of the electronic device hardly returns to the initial level after being powered off. In this situation, if the electronic device is powered on again when the discharging process of residual voltage is not finished yet, abnormal operation may happen so that the electronic device cannot be turned on. The prior art device for discharging residual voltage is complicated and production cost cannot be saved.